Absorbent articles, such as diapers, sanitary towels, incontinence garments, medical dressings and the like, have widespread utility in both domestic and institutional settings for such purposes as the care of infants, the management of menstrual discharge, the management of bodily efflux or exudate and the management of incontinence. However, a known problem associated with the use of absorbent articles is that the articles have a finite capacity for absorption which, if exceeded, will cause the absorbent article to become ineffective, e.g., to leak, or at least to fail to absorb further.
Therefore, users of such articles, or their carers, must predict when an absorbent article is nearing its absorbent capacity and must then take steps to replace the article before capacity is reached. In situations where there are many users of such absorbent articles but relatively fewer carers, such as in institutional settings, the management of the capacity of the various absorbent articles in use becomes a significant administrative burden.
Since absorbent articles are available in a variety of absorbent capacities, the user or carer must also determine, from those products which are available, which capacity of article to select. For example, in some circumstances it may be preferable to select an article of a lower capacity which is changed more frequently in contrast to an article of relatively larger capacity which is changed less frequently. Factors influencing this choice will be the nature of the absorption required, i.e., whether intermittent large quantities or a continuous smaller rate, as well as the total volume expected to be absorbed during a given period of time.
It can be very difficult for a user or carer to accurately predict or determine the state of an absorbent article, in terms both of utilised absorbent capacity and the need for the article to be replaced. Even where the absorbent demands on the article are reasonably predictable, a period of record-keeping and experimentation is required before a pattern may be established, and appropriate absorbent articles provided.
Systems which are able to alert the user or carer to saturation or impending saturation of the absorbent article are therefore of benefit. Furthermore, systems which are able to monitor the usage pattern of a particular absorbent article, and of a series of absorbent articles associated with a particular individual, over a period of time, are of particular benefit.
Such systems may take the form of an absorbent article having embedded sensors which connect to a logger unit to monitor and record the sensor data over time. The sensors can, for example, be moisture sensors. When the absorbent capacity of the absorbent article is approached or exceeded, the user or the carer can be notified, on the basis of the recorded sensor data, that the absorbent article requires replacement.
Additionally, data obtained from a particular user over time can be used to monitor both the health of the user and the appropriateness of the absorbent article for that user over an extended period and can be used to provide better information for the care of the user. For example, an event, such as an incontinence event, leading to saturation of the article can be predicted and action, such as toileting action, taken before the event occurs.
One exemplary system is shown in FIG. 1, in which an absorbent article 400, exemplified here as a diaper and having a waistband 410 and an absorbent area 420, is provided with a logger unit 300 attached to the waistband 410 and having sense wires 430 extending from the logger unit 300 running through the absorbent area. The sense wires 430 may be used to detect moisture, for example by detecting changes in the conductivity between the wires. The sense wires may be only partly exposed to the absorbent area, for example by providing insulation, to localise the region of sensing. The particular wiring pattern depicted is wholly exemplary, and will be selected according to the sensing requirements.
The logger unit 300, including data-logging electronics such as a power source, processor, memory, instruction store, data store, communications bus, and data link interface, which cooperate to store, process, and/or forward the data derived from sense wires, is connected by data link 500 to a data receiver 600. In the example of FIG. 1, data link 500 is a wireless data link, and data receiver 600 is a wireless data receiver. However, it is also possible that a docking functionality can be provided between the logger 300 and a docking station functioning as data receiver 600 to transfer data recorded in the logger unit 300 when the logger unit 300 is placed into the docking station. In a further alternative, data link 500 can be provided over the cellular telephone network, in which case data receiver 600 may be implemented as a cellular base station.
The data received at data receiver 600 is then transmitted by a further data link 700 to data processing equipment 800, exemplified as computer terminal 810 and output device 820 mutually connected by data link 830. Here, the computer terminal 810, which is an example of a general purpose data processing device, conducts processing on the sensor data received from the logger unit 300 via data links 500 and 700 and data receiver 600 and takes action based on the same, for example by outputting alerts, predictions, or statistics via output device 820. Here, the output device is shown as a line printer, but could, for example, be another form of hard copy printer, a visual display unit, a visual alarm panel, or an audio output device, without limitation.
Such a system may provide a powerful tool for the management of users of absorbent articles.
However, absorbent articles are conventionally disposable absorbent articles for reasons of hygiene and convenience. Although reusable absorbent articles are known, they are rarely used, especially in institutional and clinical settings, for reasons of economy and hygiene, amongst others.
Therefore, in the arrangement of FIG. 1, if the logger unit 300 is directly connected to sensor wires 430, which extend through the article 400, when the absorbent article 400 is to be discarded after a use, the logger unit 300 must be discarded also. As the logger unit 300 is generally far more costly than the article 400 to manufacture, it is advantageous to provide the absorbent article 400 with a receptacle for receiving the ends of the sensor wires 430 at conductive terminals, and for accommodating the logger unit in a manner which permits the conductive terminals of the receptacle to contact corresponding conductive terminals of the logger unit when the logger unit is engaged with the receptacle. Such an arrangement is disclosed in Applicants' International Patent Application PCT/EP2013/055686, which was filed on 19 Mar. 2013. In this manner, when an absorbent article is ready for disposal, the datalogger can simply be disengaged from the receptacle by the care giver, and then engaged with the receptacle attached to the new absorbent article. This ensures that, when a new diaper is provided to an end user, the same logger is used so there is no potential for confusion regarding which data pertains to which end user.
WO-A-2011/054045 discloses a system for monitoring incontinence in one or more subjects wearing an absorbent article. In this system, a sensor monitors changes in resistance between electrodes provided in the absorbent article to identify the presence of wetness in the absorbent article. The magnitude of the change in resistance is detectable by a transmitter couplable with the sensor which, in use, transmits a continence-related data signal to a processor. The sensor may use a range of indicators to generate a continence-related data signal, such as changes in temperature, capacitance, inductance, impedance, presence of biological specimens, gases etc. Hence, in the system of WO-A-2011/054045, continence-related data is produced and transmitted only if a particular event, such as the presence of wetness in the absorbent article, occurs. It cannot be determined from the data thus obtained whether the absence of continence-related data for a certain time interval is due to the absence of such events or indicators or due to a failure or malfunction of the system. Therefore, such failures or malfunctions may be difficult to detect.
Hence, there remains a need for methods of monitoring an absorption state of an absorbent article and methods of processing data indicating this absorption state which allow for a reliable and efficient detection of such failures, as well as for devices for performing these methods.